摘要:
The process features concurrent feeds into the liquid phase of a prepolymerization reaction mixture. These feeds are: a) separate continuous or substantially continuous feeds of (i) a polymerizable vinylolefin, and (ii) a solution in an organic liquid solvent of a metallocene and an aluminoxane and/or metallocene-aluminoxane reaction product; or b) separate continuous or substantially continuous feeds of (i) a polymerizable vinylolefin, (iii) a metallocene optionally in an organic liquid solvent or diluent, and (iv) an aluminoxane optionally in an organic liquid solvent or diluent; or c) separate continuous or substantially continuous feeds of (i) and (ii) and at least one of (iii) and (iv). Particles of catalytically-active, prepolymerized, self-supported olefin polymerization catalyst composition are formed in the reaction medium. The metallocene used as the feed or in making up the feed has at least one polymerizable olefinic substituent in the molecule.
摘要:
A highly efficient method of producing alkyl mercaptan and/or dialkyl monosulfides which involves employing carbon dioxide as an internal coolant is described. Only negligible amounts of carbonyl sulfide were formed. In addition, relatively easy separation of carbon dioxide from the reaction mixture facilitates an efficient coolant recycle process, giving a simple and effective mode of temperature control.
摘要:
A mixture comprised of about 60-85% of 2,4-toluenediamine (2,4-TDA) and about 15-40% of 2,6-toluenediamine (2,6-TDA) is melted, the temperature of the mixture is lowered to a 2,4-TDA nucleation temperature, and the temperature of the mixture is gradually reduced from the nucleation temperature to about 65 to about 70° C. The resultant mixture is in the form of a solids phase enriched in 2,4-TDA, and a novel and useful liquid phase enriched in 2,6-TDA. These phases are separated. Preferably the solids are further purified by “sweating” them and removing the sweated liquid impurities. The sweated liquid can be recycled together with another charge of a mixture comprised of 2,4-TDA and 2,6-TDA. 2,4-TDA can be produced with a purity of 96-99%.
摘要:
Compositions and methods are described wherein a styrenic polymer is rendered flame retardant by incorporation therein before, during or after its formation, a combination of (a) at least one organic phosphorus additive that (i) is halogen-free, and (ii) is composed solely of carbon, hydrogen, and phosphorus, and optionally and preferably one or more of the elements nitrogen, oxygen, and sulfur; and (b) elemental sulfur; in proportions such that (i) the sulfur content from b) is less than 2 percent by weight of the weight of the styrenic polymer plus the weight of a) and b), and (ii) the styrenic polymer plus ingredients a) and b) can provide test specimens which exhibit an LOI of at least 24 if tested in accordance with ASTM Standard Test Method D 2863-87.
摘要:
Mixtures of isomeric alkylthiated mononuclear aromatic amines comprising in the range of about 30 to about 70 mole percent of (i) at least one 3,5-di(alkyl-thio)-2,6-diamino-1-alkylbenzene and in the range of about 30 to about 70 mole percent of at least one 3,5-di(alkylthio)-2,4-diamino-1-alkylbenzene, such mixture containing at least about 90 mole percent of (i) and (ii), and optionally containing up to 10 mole percent of one or more isomers of (i) and/or (ii). An alkyl group may be present as a substituent in lieu of a hydrogen atom in the remaining ring position. These mixtures are useful as curatives or extenders in processes for making polyurethanes, polyurethane-ureas, and polyureas.